The invention relates to improvements in the operation of electrosurgical instruments for coagulating and cutting biological tissue with argon. In particular, the invention relates to a device for enhancing the safety and efficiency of a hand-operated electrosurgical handset which is used in conjunction with a flow of argon to perform the desired coagulation by electrosurgical fulguration or to provide electrosurgical cutting and to an improved method for performing electrosurgical operations in the abdominal cavity.
Electrosurgical fulguration comprises the application of electric sparking to biological tissue, for example, human flesh or the tissue of internal organs, without significant cutting. The sparking is produced by bursts of radio-frequency electrical energy generated from an appropriate electrosurgical generator. Generally, fulguration is used to dehydrate, shrink necrose or char the tissue, which operations are primarily to stop bleeding and oozing, or otherwise to seal the tissue. These operations are generically embraced by the term "Coagulation". Electrosurgical cutting comprises electric sparking to tissue with a cutting effect.
As used herein the term "electrosurgical handset or handset" is intended to mean an instrument comprising a surgical handpiece to which is attached an electrode (the "active electrode"), that may be detachable or fixed. The handset may be operated by a handswitch or a foot switch. The active electrode is an electrically conducting element usually elongated in the form of a thin flat blade with a pointed or rounded distal end, or an elongated narrow cylindrical needle that may be solid or hollow with a flat, rounded, pointed or slanted distal end. The term "electrode" when used herein will generally refer to the active electrode. Electrodes as blade electrodes, loop or snare electrodes, needle electrodes and ball electrodes are available.
The handset is connected to a suitable electrosurgical generator which generates the high frequency electrical energy necessary for the operation of the electrosurgical handset. An electrosurgical generator suitable for use with electrosurgical electrodes and handsets is disclosed in U.S. Pat. No. 3,699,967, the disclosure of which is incorporated herein by reference. When an operation is performed on a patient with a handset, electrical energy from the electrosurgical generator is conducted through the active electrode to the tissue at the site of the operation and then through the patient to a return electrode, placed at a convenient place on the patient's body, to return via a patient pad or plate made of conductive material to the electrosurgical generator. A suitable circuit is illustrated schematically in U.S. Pat. No. 3,699,967.
The use of a stream of argon gas in conjunction with an electrosurgical electrode is in U.S. Pat. No. 4,060,088 wherein an electrosurgical method and apparatus for coagulating tissue by fulguration that involves establishing an electrical discharge in argon gas flowing through a tubular electrode to which high-frequency electrical energy is applied.
U.S. Pat. No. 4,040,426 discloses a method and apparatus wherein the argon gas flow disposed adjacent the end of an active electrode produce a primary electrical discharge in the gas and the apparatus includes a second electrode, electrically isolated from any source of biasing potential, which facilitates the establishment of an auxiliary electrical discharge from an electrostatic charge generated by the argon gas. U.S. Pat. No. 4,057,064 discloses a method and apparatus for producing coagulation of tissue with a flow of argon gas and an active electrode.
Gas surgical pencils have a pair of switches that start and stop argon flow as disclosed in U.S. Pat. No. 5,217,457; U.S. Pat. No. 5,244,462 and U.S. Pat. No. 5,088,997 all assigned to the same assignee, Valleylab Inc Boulder, Colorado as this disclosure. The switch for directing argon flow mounts on the electrosurgical pencil. A gas line for argon and a pair of switches for the electrosurgical generator coagulation or cut wave forms are on the pencil. The argon electrosurgical pencil includes an electrical cable with wires for connection directly to the gas surgical unit to trigger the flow of argon gas when the electrosurgical energy is called for by the surgeon. The gas delivery control is on the pencil and controls the gas delivery from the separate on and off switch buttons and wires connecting to circuits integral with the gas surgical unit. In addition to the three wires connected between the argon electrosurgical pencil and the gas surgical unit, there is another wire for providing electrosurgical energy from the electrosurgical generator. Cut and coagulation wave forms are controlled by buttons therefor on the gas surgical pencil.
U.S. Pat. No. 4,781,175 discloses an electrosurgical technique for achieving coagulation involving conducting a predetermined ionizable gas not containing oxygen in a jet to tissue and conducting electrical radio-frequency energy in ionized conductible pathways in the gas jet.
Argon supplies those metering orifices and valves provide varying flow rates of argon gas to the electrosurgical tip. The concept of using metering orifices and valves is shown in U.S. Pat. No. 5,427,104 wherein the volume of flow is metered. A three way valve connects to receive the metered volume. U.S. Pat. No. 3,688,770 discloses valves and restrictions. U.S. Pat. No. 3,885,590 has a pressure regulator and a metering orifice with a valve to bleed to atmosphere excess pressure and protect the patient. U.S. Pat. No. 5,292,304 discloses digital control of the valves before the metering orifices in an insufflator for providing various flows. There are a variety of well known approaches for controlling gas flow by metering orifices.
Percutaneous surgery through a trocar inserted cannula and particularly with an opening through the external tissue of a patient, such as an abdominal wall has become an important means to minimize the extent of surgical invasion. The lessening of invasion improves the cosmetic result, shortens recovery and lowers the cost. Endoscopic or laparoscopic internal surgical procedures and equipment are available and in use for a variety of medical operations including gall bladder, bowel and gynecological surgery.
U.S. Pat. No. 3,595,239 discloses a catheter tube having an obturator in the form of an electrode passing coaxially therethrough. The obturator electrode is connected to an electrosurgical generator in order to provide high frequency energy used to divide or cut tissue thereby forming a passage for the catheter coaxially about the obturator to pass therewith through the tissue. The tip of the obturator extends beyond the catheter tip and cuts the path for its passage. The catheter moves along with the obturator electrode by means of a ring disposed about the obturator proximal to the tip and inside the tip of the catheter.
U.S. Pat. No. 4,874,362 has a system and its use for controlling the addition of insuflation gas. The detected gas flow at a regulated pressure is repeatedly compared at successive clock intervals with a preset flow rate value and regulated to a level of 50 millimeters of mercury higher than the preset nominal pressure. The purpose of this patent is to eliminate magnetic valves and to allow for the constant control, monitoring and delivery of flow as required to the body cavity. The system looks at the pressure and adjusts the input or flow of gas on a frequent basis as controlled by pulsations established by the software in this computer operated circuit.
U.S. Pat. No. 4,971,034 checks pressure on a suction tube communicating with a channel through an endoscope against a reference pressure so that a control may operate the suction source to regulate the pressure between that found and that desired. U.S. Pat. No. 5,047,010 discloses an insuflation control including a fluid supply with a pressure valve for insuflation of the body cavity and means for measuring the actual value of fluid pressure in the cavity. A circulation pump connected to a filter in communication with the body cavity for drawing off fluid and delivering it back to the probe through a second fluid circuit wherein the two circuits have common portion extending to the probe and a means associated with the pump compensates for dynamic pressure independently of the delivered flow by response to partial vacuum on the inlet side of the pump.
U.S. Pat. No. 5,098,375 has a pressure sensor control and valve operated thereby to regulate the addition of gas to make up for that which is absorbed and that which is lost through leakage and debris removal, i.e., constant insuflation pressure. U.S. Pat. No. 5,139,478 has a source of insuflation gas and a suction unit, a delivery line between source and a gas inlet of a surgical laser equipped endoscope, part of endoscopic tube is introducable into the body cavity with the insuflation gas from the source. Pressure adjustment means on the delivery line limit the pressure gas insuflated for maximum flow and an exhaust for the gas in the body cavity connects to the suction unit and passes through the endoscope. If the flow is greater than two liters per minute per centimeter of water column, insuflation gas pressure is recirculated.
U.S. Pat. No. 5,246,419 has an intra-abdominal insuflation apparatus and a plurality of gas delivery tubes connected in parallel to a source of insuflation gas for the body cavity, a means for measuring the insuflation pressure in the cavity separate from the flow of gas in each of the tubes and plurality of means for controlling flow of insuflation gas to the pressure sensing means and automatically adjusting the flow independently in each of the tubes.
It has been found that if at least one stream or jet of filtered argon gas when directed into the abdominal cavity may change the insuflation pressure. The argon electrosurgical handset may be used both for cutting and coagulation and the delivery of argon can change the insuflation pressure or clog a passage way from the abdominal cavity.
The present invention provides improvements in abdominal cavity surgery with the techniques disclosed in the above patents, but since the basic concept of initiating an electrical discharge is an argon gas flow and the general circuitry for carrying out the procedure is involved with apparatuses and methods of the present invention, the disclosure in each and all of the aforementioned patents is incorporated herein by reference.